Medical instrument

ABSTRACT

The invention relates to a medical instrument with a shaft, a handle mounted on the proximal end of the shaft, and a tool mounted on the distal end of the shaft and capable of being activated by means of the handle, where the handle and the tool are in active connection by means of at least one activation rod. To make it possible for the tool, in particular as a one-way tool, to be secured simply and rapidly on the activation rod, the invention proposes that the tool should have a tool shaft for securing it to the activation rod and that the tool shaft and the activation rod in order to be secured to one another should have protuberances and/or recesses, which can be engaged, at least partially as a form-locking connection, with corresponding recesses or protuberances of the other respective component.

This application claims priority from pending German Patent ApplicationNo. 02 020 720.5 filed on Sep. 14, 2002.

FIELD OF THE INVENTION

The invention relates to a medical instrument with a shaft, a handlemounted on the proximal end of the shaft, and a tool mounted on thedistal end of the shaft and capable of being activated by means of thehandle, where the handle and the tool are in active connection by meansof at least one activation rod.

Conventional medical instrument are frequently used in practice asgripping, securing, and/or cutting tools. Thus, the jaw members can haveblades for severing tissue or blunt surfaces for holding severed tissue,for instance, or stanching blood vessels.

In order to make the most flexible possible use of a medical instrumentof this kind, on the one hand, and, on the other, to facilitate cleaningof the instrument, the known practice is to connect the tool detachablywith the activation rod. The known connections between tool andactivation rod, however, had the disadvantage that, as is known from EP0577423 B1, they are of very expensive construction as screw-in ornesting connections, and thus simple, rapid, and thus cost-efficienttool replacement is not possible with these known instruments.

A conventional medical instrument is known from U.S. Pat. No. 5,496,347.In this known instrument, the activation rod is secured directly on thejaw members of the tool. For this purpose, the distal end of theactivation rod has recesses into which cams configured on the jawmembers engage. In order to secure the connection of the activation rodwith the jaw members in the radial direction of the shaft, on the onehand the activation rod is mounted between the two jaw members and onthe other hand the distal end of the shaft is configured so that theactivation rod and the jaw members in this coupling area are surroundedby a housing, which is arranged inside the hollow shaft and in additionserves as a guide for the activation rod.

This known construction allows the tool to be secured on the activationrod without screwing connections; however, the complexity ofinstallation—especially because of the use of the additional housing andthe connection of the activation rod with the individual jaw members ofthe tool—is so great that, here too, simple, rapid, and thuscost-effective tool replacement is not possible with this instrument.Consequently it is the aim of the invention to design a medicalinstrument of the aforementioned type in such a way that the tool can besecured, especially as a one-way tool, simply and rapidly on theactivation rod.

The aim is fulfilled according to the invention in that the tool has atool shaft for purposes of securing it to the activation rod, and thatthe tool shaft and the activation rod, for purposes of securing them toone another, have protuberances and/or recesses, which can be engaged,at least partially as a form-locking connection, with correspondingrecesses or protuberances of the other respective component.

Thanks to the invention's design of the coupling areas of the tool andactivation rod, it is possible for the first time to secure thecomponents that are to be joined together without additional securingelements, essentially by means of a socket connection. The flexibilityof the instrument to be used with various tools is consequentlyincreased because the protuberances and/or recesses for securing theactivation rod to the tool are configured on a tool shaft of the tool.

To ensure the widest possible use of the inventive medical instrument,according to a preferred embodiment it is proposed that the tool shouldbe able to be secured to the activation rod in such a way that forces inthe longitudinal direction of the activation rod and/or torsion forcescan be transmitted to the tool.

The tool and activation rod are connected preferably by means of amovement that is essentially perpendicular to the longitudinal axis ofthe activation rod, whereby this motion can be executed as an insertionmotion in the direction perpendicular to the longitudinal axis of theactivation rod or as a rotating motion around an axis perpendicular tothe longitudinal axis of the activation rod.

It is also proposed with the invention that the tool should bedetachably fixable to the tool. In this configuration, the tool shaftfor instance can be used as an adapter in order to bring various toolswith the adapter that has an identical activation rod connection intoconnection with the activation rod.

According to a preferred embodiment of the invention, the activation rodand the tool shaft are configured to have an essentially roundcross-section. This configuration is particularly advantageous whentorsion forces are to be transferred to the tool.

According to a first practical embodiment with essentially roundcross-section of the activation rod and the tool shaft, in the area ofthe distal end of the round activation rod at least on one side atangential leveling is configured on the activation rod in such a waythat the distal end of the activation rod also has a head area thatextends beyond the leveling in radial direction. The proximal area ofthe tool shaft thus has an overlapping for receiving the head area ofthe activation rod as well as a recess corresponding with the tangentialleveling of the activation rod.

While it is possible, with the aforementioned embodiment, to configurethe leveling asymmetrically, it is proposed according to a secondalternative embodiment that the tangential leveling of the activationrod should be configured as a center rod leveled from two opposite sidesand the corresponding recess on the tool shaft is configured as a radialslit.

It is further proposed with the invention that the activation rod andthe tool can be coupled with one another by means of at least one studrunning diagonally to the instrument longitudinal axis, where the studis configured either on the activation rod or on the tool shaft andengages in a corresponding recess in the tool shaft or in the activationrod.

Use of the stud to connect the activation rod with the tool can thus beconsidered in addition or as an alternative to the configuration of theoverlapping and of the head area.

It is, finally, proposed with the invention that a spring element shouldbe included in order to transmit pulling or pushing forces in thecoupling area between the activation rod and the tool. Besides thepossibility of using the spring power of the spring element, forinstance in order to open the tool in applying pushing pressure, thespring force reinforces the form-locking link of the activation rod andtool shaft components.

Additional characteristics and advantages of the invention can be seenfrom the following description of the associated illustrations, in whichthree embodiments of an inventive medical instrument are depictedschematically as examples. The illustrations are as follows:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A schematic lateral view of an inventive medical instrument

FIG. 2 a A perspective lateral view of an activation rod and a toolaccording to a first embodiment of the invention in assembled condition.

FIG. 2 b A view according to FIG. 2 a, but depicting the activation rodand the tool in a position detached from one another.

FIG. 3A view according to FIG. 2 b, depicting a second embodiment of theinvention

FIG. 4A view according to FIG. 2 b, depicting a third embodiment of theinvention

DETAILED DESCRIPTION OF THE DRAWINGS

The illustration in FIG. 1 shows a lateral view of a medical instrument1, whose power transmission mechanism can be used in many ways, such asfor punching, cutting, as a needle holder, to secure instruments, and soon.

The illustrated medical instrument 1 consists essentially of a hollowshaft 2 having on its proximal end a handle 3 which consists of a rigidgripping member 3 a and a gripping member 3 b that can be rotated inrelation to the rigid gripping member 3 a. The distal end of the shaft 2has a tool 4 which is made up of two jaw members 4 a and 4 b that canrotate with respect to one another around a common rotation point 5.

As can be seen from the views in FIGS. 2 a to 4 in connection with thecomposite view of FIG. 1, the jaw members 4 a and 4 b of the tool 4 andthe rotatable gripping member 3 b of the handle 3 are connected with oneanother by means of an activation rod 6 in such a way that the jawmembers 4 a and 4 b can be moved from the closed position (striped areain FIG. 1) into the open position (dotted section in FIG. 1) or viceversa by displacement of the gripping member 3 b. The respectiveresulting position of the rotatable gripping member 3 b is also stripedin FIG. 1 (indicating the closed position) and dotted (for the openposition).

The illustrations in FIGS. 2 a to 4 also show that the activation rod 6is not directly secured to the tool 4, but rather to a tool shaft 7,which in the illustrated embodiments is detachably connected with thetool 4 and in direct active connection with the jaw members 4 a and 4 bof the tool 4.

To connect the activation rod 6 with the tool shaft 7, the illustratedembodiments indicate, both on the activation rod 6 and on the tool shaft7, protuberances 8 and recesses 9 which correspond with correspondingprotuberances 8 and recesses 9 of the other respective component (6, 7or 7, 6) in such a way that they can be brought together in form-lockingengagement. In the illustrated embodiments, this mutually correspondingconfiguration of the protuberances 8 and recesses 9 can be seenespecially in FIG. 2 a, which shows a continuous round cross-section ofactivation rod 6 and tool shaft 7 when they are joined together. Theactivation rod 6 and the tool shaft 7 can also, of course, havecross-section shapes that are non-round and/or differ from one another.

In the embodiments illustrated in FIGS. 2 a to 4, the recesses 9 on theactivation rod 6 are formed by tangential levelings which are configuredon two opposite sides on the activation rod 6 in such a way that theactivation rod in the area of this leveling consists only of a narrowmiddle stud 9 a. The distal end of the activation rod 6 forms a headarea 8 a which overhangs the middle stud 9 a in radial direction andforms a protuberance 8.

To receive the middle stud 9 a as well as the head area 8 a of theactivation rod 6, on the tool shaft 7 a radial slit is configured as arecess 9 and an overlapping 8 b is configured as a protuberance 8. Ascan be seen from FIG. 2 a, the respective protuberances 8 and recesses 9of the activation rod 6 and tool shaft 7, when joined together, blendtogether in such a way that they are interlocking in a form-lockingconnection.

Alternatively to the illustrated embodiments, in which the recess 9 isconfigured on the activation rod 6 as a symmetrical two-sided levelingof the activation rod 6 forming the middle stud 9 a, it is also possibleof course to perform the leveling asymmetrically on just one side or onboth sides to strongly varying degrees. The middle stud 9 a can thus, asshown, be four-sided but can for instance have likewise a cross-sectiontapering in the insertion direction. It is also possible that thecross-section of the middle stud 9 a changes in the axial direction.

The second embodiment shown in FIG. 3 differs from the one in FIG. 2 bin that a stud 10 is also arranged in the tool shaft 7 runningdiagonally to the instrument longitudinal axis, which stud 10 engages ina corresponding recess 11 in the activation rod 6. In the illustratedembodiment the stud 10 is mounted in a hole 12 bored in the tool shaft7. An alternative possibility is to install the stud 10 on theactivation rod 6 and to configure the corresponding recess 11 on thetool shaft 7, so that it is also possible in both cases to configure thestud 10 as a single unit with the activation rod 6 or the tool shaft 7.

The third embodiment, illustrated in FIG. 4, differs from the one FIG. 2b in that a spring element 13 is mounted in the coupling area betweenthe activation rod 6 and the tool 4. The spring element 13, sketchedonly as an example, can serve, for instance in applying pushingpressure, to open the tool 4 by spring action, or else to reinforce theform-locking joining of the components, i.e. activation rod 6 and toolshaft 7. If the spring element 13 is mounted between the tool 4 and thetool shaft 7, the spring element 13 can cause an activation of the tool4 entirely in a single direction (opening or closing). The othercorresponding motion (closing or opening) can then be produced by theactivation of the activation rod 6.

In particular in the configuration of the coupling area between theactivation rod 6 and the tool 4 with a spring element 13, it is possibleto dispense with the head area 8 a shown in FIGS. 2 a to 4 on theactivation rod 6.

In this case no pulling force can be transmitted to the tool 4 by meansof the activation rod 6, but only pushing and torsion forces. Thepulling forces in this embodiment can be assumed by the spring element13, whose spring force closes the tool 4 or whose spring force must beovercome by means of the pushing force applied by means of theactivation rod 6 to open the tool 4.

Of course, construction solutions are also possible in which a pullingforce is applied by means of the activation rod 6 and the pushing forceis produced by the spring power of the spring element 13.

The medical instrument 1 is activated as follows: First, from theseparated starting position illustrated in FIG. 2 b, the activation rod6 and the tool shaft 7, by means of a motion essentially perpendicularto the longitudinal axis of the activation rod 6, are brought intoengagement with one another by matching the reciprocal protuberances 8and recesses 9 so as to produce the joined configuration illustrated inFIG. 2 a.

Then the activation rod 6 with the proximal end in front is introducedinto the hollow shaft 2. To connect the activation rod 6 with therotatable gripping member 3 b of the handle 3, on the proximal end ofthe activation rod 6 a toggle head 14 is arranged which can be insertedto engage with a corresponding spherical recess (not illustrated) on thegripping member 3 b.

For secure action of the gripping members 3 a, 3 b of the handle 3, thehandles have finger loops 3 c on their free ends. In the illustratedembodiment the gripping member 3 b can be rotated around a rotation axis15 with respect to the other, rigid gripping member 3 a.

Through the coupling of the rotatable gripping member 3 b by theactivation rod 6 with the tool 4, the jaw members 4 a, 4 b of the tool 4open and close.

Thanks to the simple coupling of the activation rod 6 on the tool 4 orthe tool shaft 7 by the formation of the protuberances 8 and recesses 9,new tools 4 can be especially simply and quickly secured on theactivation rod 6, so that the use of one-time tools is particularlyfacilitated.

The coupling of the activation rod 6 on the tool 4 or tool shaft 7 is,in addition, configured in such a way that forces can be transmitted inlongitudinal direction of the activation rod 6 and torsion forces can betransmitted on the tool 4.

KEY

-   1 Medical instrument-   2 shaft-   3 handle-   3 a rigid gripping member-   3 b rotatable gripping member-   3 c finger loops-   4 tool-   4 a jaw member-   4 b jaw member-   5 rotation point-   6 activation rod-   7 tool shaft-   8 protuberance-   9 recess-   9 a middle stud-   9 b slid-   10 stud-   11 recess-   12 bore hole-   13 spring element-   14 toggle head-   15 axis of rotation

1. Medical instrument with a shaft, a handle mounted on the proximal endof the shaft, and a tool mounted on the distal end of the shaft andactivated by the handle, where the handle and the tool are in activeconnection by means of at least one activation rod and the tool can besecured detachably by means of a tool shaft on the activation rod, forwhich purpose the tool shaft and the activation rod have protuberancesand/or recesses, which can be joined in a form-locking connection, atleast partially with corresponding recesses or protuberances of theother respective component wherein the recesses and protuberancescorresponding to one another are configured in such a way that the tooland the activation rod can be brought into engagement with one anotherby means of a movement exclusively in one direction essentiallyperpendicular to the longitudinal axis of the activation rod, and thecomponents coupled to one another are nonmoveably fixed relative to oneanother in all directions other than the one direction essentiallyperpendicular to the longitudinal axis of the activation rod; whereinthe tool can be secured to the activation rod in such a way that forcescan be transmitted in the longitudinal direction of the activation rodand/or torsion forces can be transmitted to the tool; wherein the tooland the activation rod can be connected with one another by means of amotion essentially perpendicular to the longitudinal axis of theactivation rod; wherein the activation rod and the tool shaft areconfigured as essentially round in cross-section, and wherein in thearea of the distal end of the round activation rod at least on one sidea tangential leveling is formed on the activation rod in such a way thatthe distal end of the activation rod further has a head area overhangingthe leveling in radial direction and the proximal area of the tool shafthas an overlap for receiving the head are of the activation rod and arecess corresponding to the tangential leveling of the activation rod.2. Medical instrument according to claim 1, wherein the tangentialleveling of the activation rod is configured as a middle stud leveledfrom two opposite sides and the corresponding recess on the tool shaftis configured as a radial slit.
 3. Medical instrument according to claim2, wherein the activation rod and the tool can be coupled to one anotherby means of at least one stud running diagonally to the instrumentlongitudinal axis, where the stud on the one hand is stored in a holdbored in the activation rod or in the tool shaft and on the other handengages in a corresponding recess in the tool shaft or in the activationrod.
 4. Medical instrument according to claim 3, wherein, for thetransmission of pulling or pushing forces in the coupling area, a springelement is placed between the activation rod and the tool.
 5. Medicalinstrument according to claim 4, wherein the tool can be activated bymeans of the spring element.